The present invention is concerned with ceiling cassette type air conditioner mounted to the ceiling of the room to be air conditioned, and in particular, it relates to the improvement of the mounting of temperature sensor that detects the temperature of the room air which is sucked in and guided by the bell-mouth, and the improvement of the arrangement of electrical parts box versus the bell-mouth as well as the mounting structure of the electrical parts in the electrical parts box.
The ceiling cassette type air conditioner comprises an enclosure which is open at the bottom, a blower located at approximately the center of this enclosure, heat exchangers arranged around the blower, a bell-mouth that is installed so that its upper opening portion is facing the axial direction of the blower, and a decorative panel exposed to the room to be air conditioned from the ceiling surface, and which possesses a suction inlet facing the bottom opening portion of the bell-mouth, and which possesses blower outlets around the suction inlet, and blocks the lower opening portion of the enclosure.
Therefore, only the decorative panel that possesses the suction inlet and the blower outlet is exposed from the ceiling panels, that is, the enclosures of the ceiling cassette type air conditioners are embedded above the ceiling panels of the room to be air conditioned, and the inhabitants do not receive the sense of oppression at all, so there is a tendency of their usage increasing.
In such an air conditioner is equipped with electrical parts that control motor-driven parts such as a blower, and electrical parts that receive detection signals such as remote controller (remote control operating panel) as well as operation instruction signals transmitted from various detection means, and change them into control signals.
The electrical parts consist of many electric parts and electronic parts, and because of the limited space in the enclosure, the electric parts are attached to a single control board, and after making electrical connections, they are accommodated in an electrical parts box.
Furthermore, inside of the enclosure, heat exchangers, a drain pan to receive the drain water generated from the heat exchangers, a blower to blow the room air through the heat exchangers, and a bell mouth to guide the room air smoothly to the blower are arranged.
Hitherto, there were problems related to arrangement of electrical parts box against the aforementioned bell-mouth and mounting structure of the electrical parts that are accommodated in the electrical parts box.
In other words, as electrical parts accommodated in the electrical parts box, there are all kinds of parts, for instance, small-sized electronic parts such as integrated circuits, resistances, and FET, a rather big-sized large capacity condenser, and medium-sized parts such as switching transformer, small capacity condenser, noise filter, etc. All of these parts are mounted to a single board for the convenience of circuit designing. As a result, the total height dimension of the electrical parts box uses the control board as the basis, and for instance, the big-sized electrical parts such as the large capacity condenser, are accommodated with dimensions having allowance. As a result, the electrical parts-box becomes big-sized, and it hinders the miniaturization of the unit.
In addition, for instance, as shown in FIG. 16A, the bell-mouth Ba originally has a tapered shape (cone-shaped) cross section, that is, small diameter at the top opening, and large diameter at the bottom opening, but in order to mount the electrical parts box D, a part of the tapered surface is bent back to the upper side, then bent horizontally. The electrical parts box D is mounted to the passage side of the primary air (air which is sucked in) at the lower portion of the bell-mouth horizontal plane. In the drawing S stands for the control board and E stands for the electrical parts mounted to the control board S.
On the other hand, as shown in FIG. 16B, bell-mouth Bb has a part of the tapered portion bent down vertically, then bent horizontally. The electrical parts box D is mounted above the horizontal plane of the bell-mouth on the passage side of the secondary air.
In this way, whether it is bell-mouth Ba or Bb, in order to mount the electrical parts box D, a part of the bell-mouth has to be deformed, and consequently, the bell-mouth does not take an ideal form, thereby hindering the blower performance.
On the other hand, the air conditioner, in order to conduct the pre-set air conditioning, one of the control conditions is to measure the present room temperature. This is possible by detecting the temperature of the air of the room to be air conditioned by a temperature sensor when the air is sucked in and guided by the bell-mouth, and transmitting these detection signals to the controller among the electrical parts.
As an actual temperature sensor mounting structure, a sensor supporting member is mounted to the inner surface side of the suction air guide side of the bell-mouth, and the sensor is supported by this supporter. The temperature sensor must be electrically connected with a controller which composes one of the electrical parts, but these electrical parts can secure arranging space only above the bell-mouth.
As a result, a lead wire of which one end is connected to the controller is extended from the upper part of the bell-mouth to the periphery of the sensor, then further stretched to the inner surface side of the bell-mouth. Furthermore, the other end must be connected to the temperature sensor that is supported by the sensor-supporting member. In conclusion, the total length of the lead wire becomes very long, and it has bad influence on the cost.
Not only the cost, but also at the time of maintenance when it becomes necessary to remove the bell-mouth, the sensor supporting member will have to be removed from the bell-mouth together with the temperature sensor. Furthermore, after the maintenance work is completed, the lead wire will have to be extended and connection will have to be made. Thus, there were problems such as being time-consuming, and having bad maintenance operation efficiency.
The first objective of the present invention is to obtain a bell-mouth shape having excellent blower characteristics, and to mount the electrical parts into the electrical parts box without interfering with the shape of the bell-mouth, thereby providing a ceiling cassette type air conditioner which can be designed compactly.
The present invention comprises a housing provided on the ceiling panel of a room and having a bottom opening, a heat exchanger arranged in the housing; a drain pan provided in the housing, a blower provided in the housing, a bell-mouth provided in the housing and having a bottom opening and an outer circumferential surface, an electrical part box provided in the housing and accommodating electrical part; and a decorative panel closing the bottom opening of the housing, having an inlet port opposing the bottom opening of the bell-mouth and having outlet ports surrounding the inlet port, wherein the electrical part box is arranged near that side of the bell-mouth at which secondary air flows, the electrical parts are mounted on a control board provided in the electrical part box, and those of the electrical parts which are located near the outer circumferential surface of the bell-mouth are less tall than the other electrical parts.
According to the present invention, it is possible to set the bell-mouth in a shape having excellent blowing characteristics, and without interfering such bell-mouth shape, the electrical parts inside of the electrical parts box are mounted, and this has an effect of making the unit compact.
The second objective of the present invention is to shorten the length of lead wire when mounting the temperature sensor, and at the same time, omit the extending-around operation. In addition, it aims at providing a ceiling cassette type air conditioner in which the maintenance workability can be improved.
In the present invention, at approximately the center of the open-bottom enclosure that is mounted to the ceiling, a blower is mounted, and heat exchangers are arranged around the blower. The upper opening portion of the bell-mouth is mounted so that it faces the suction side or axial direction of the blower and blocks the lower opening of the enclosure, and facing the lower opening of the bell-mouth, a decorative panel equipped with a suction inlet and blower outlets surrounding the suction inlet is installed so that the decorative panel is exposed at the ceiling level of the room to be air-conditioned. Immediately above the bell-mouth, the electrical parts such as the controller is mounted, and a through-hole is made in the bell-mouth at a position close to the electrical parts, and a temperature sensor is inserted into the through hole so that it protrudes into the room air suction side, and among the electrical parts, the sensor is connected electrically to the controller with lead wires, and made to detect the temperature of the room air.
According to the present invention, with a very simple structure of providing a through-hole portion in the bell-mouth in order to insert a temperature sensor through it, the lead wire connecting the temperature sensor and the controller of the electrical parts can be shortened, and the temperature of the air of the room to be air conditioned can be detected accurately, and detection accuracy can be secured. In case of maintenance work where it is necessary to remove the bell-mouth, the temperature sensor can be left as it is, and it will suffice by merely pulling off the throughhole portion of the bell-mouth. In addition, it is not necessary to conduct temperature sensor attachment work after the maintenance work.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.